Problem: Solve for $y$ : $23 + y = -1$
Solution: Subtract $23$ from both sides: $ \begin{eqnarray} \\ 23 + y &=& -1 \\ \\ {-23} && {-23} \end{eqnarray} $ $ \begin{eqnarray} \hphantom{23 + y} &\hphantom{=}& \hphantom{-1} \\ y &=& -1 {- 23} \\ \end{eqnarray} $ Simplify. $ y = -24$